Effect of Lung Volume Recruitment Technique on Cough Efficacy in Postextubated Patients With Ineffective Cough

An effective cough is so vital in protecting against respiratory tract infections, so the importance of an intact cough mechanism is reflected in the occurrence of pulmonary problems which are the most common cause of hospital admission in people with respiratory muscle weakness who are unable to cough effectively. Ineffective cough results in a tendency to retain bronchial secretions and an increased risk of pulmonary complications, such as frequent or recurrent pneumonia, atelectasis, and infectious respiratory problems.

Cough flow testing (expiratory flows testing) is useful as a monitoring or diagnostic tool in clinical practice and research. Both peak expiratory flows (PEF) and cough peak flows (CPF) have been described as useful clinical measures of respiratory muscle function and cough effectiveness. Cough peak flow (CPF) gives an important measure of the cough strength which determines the effectiveness of cough. It is the maximum expiratory flow recorded immediately following the opening of the glottis during normal cough. Cough effectiveness is suboptimal when cough peak flow (CPF) is less than 270 L/min.

Mechanical Ventilation "MV" has deleterious effects caused by the endotracheal intubation, including changes in mucociliary clearance and inhibition of the coughing mechanism which, in turn, favor areas of hypoventilation and atelectasis, thus increasing the risk of ventilator-associated pneumonia. Respiratory compromise due to recurrent atelectasis, inability to clear secretions, and respiratory infections also increase morbidity and mortality. Prolonged MV results in respiratory muscle dysfunction shown in diaphragmatic atrophy and contractile dysfunction (ic., Ventilator-induced diaphragmatic dysfunction "VIDD") affecting the ability of the person to cough effectively. Indeed, the onset of VIDD in both animals and humans is rapid as significant diaphragmatic atrophy and contractile dysfunction occur within the first 24 - 48 h of MV. Although suctioning of secretions from the trachea to remove tracheobronchial and upper airway secretions is the standard of care, this method is ineffective for clearing peripheral airways and basal retained secretions.

The clinical practice guides referred to patients with respiratory muscles weakness like after prolonged MV and in neuromuscular diseases recommend the usage of cough augmentation and mucociliary clearance techniques in patients with CPF < 4.5 L/s (270 L'min) and using such techniques continuously in patients with CPF < 2.7 L/s (160 L/min). Cough augmentation techniques such as LVR are supposed to be used to reinforce cough effectiveness, particularly for patients with prolonged mechanical ventilation. So, the importance and strength of this study are to assess the effects of the LVR technique as a cough augmentation mean on CPF of post-extubated patients with an ineffective cough which can cause risky respiratory complications may lead to death in confronting to effects of traditional chest physiotherapy and suctioning and therefore, their therapy or management program can be precisely and appropriately planned. Moreover, the identification of effective, safe measures to optimize cough efficacy is, therefore, key to improving quality of life and minimizing morbidity & mortality rates in those patients. Additionally, as a secondary purpose to determine how much the LVR method, for augmenting CPF. is useful in enhancing the success of extubation and reducing the rate of re-intubation that indicated if extubation failure occurred.